Grinding methods

ABSTRACT

Method of grinding a spherical surface by relatively rotating a work piece in engagement with the shaped periphery of a grinding wheel while spinning the wheel about its axis.

nited States Patent 284, 289 S, 325, 5, 90, 105; 125/11 AT [56]References Cited UNITED STATES PATENTS 3/1881 l-lutter 10/ l 899 Gennert6/1909 Conner 1 1/1925 Powell 3/1940 Andersen 12/1956 Jones 2,804,8689/1957 Coup 3,289,354 12/1966 Stevens et a1.

Primary Examinerl ,ester M. Swingle Attorney-Johnston, Root, OKeeife,Keil, Thompson &

Shurtleff ABSTRACT: Method of grinding a spherical surface by relativelyrotating a work piece in engagement with the shaped periphery of agrinding wheel while spinning the wheel about its axis.

minnow: 4:912 3.631.641

0v vzw ran HAROLD W. SCHOL IN GRINDING METHODS This is a division of mycopending application, Ser. No. 652,743, filed July 12, 1967, now U.S.Pat. No. 3,522,678 dated Aug. 4, 1970, which in turn was a division ofmay earlier filed copending application, Ser. No. 452,787, filed May 3,1965, now abandoned.

The present invention relates in general to grinding methods, and hasmore particular reference to new and improved methods of formingspherical surfaces by grinding procedures, the invention pertainingespecially to the formation of a razor blade having a ground edge at andaround the periphery of an opening in the blade.

An important object of the invention is to provide methods of grindingspherical surfaces in work pieces; a further object being to provide acutting edge at the periphery of an opening in blade element; anotherobject being to provide a razor having a ground cutting edge at andperipherally of a hole in a razor blade element; a still further objectbeing to provide a method of grinding a spherically domed surface in awork piece.

Another important object of the invention is to form a shaving edge atthe margin of a hole in a razor blade element by grinding the samespherically on one side of the blade.

Another important object is to grind a spherical surface on a work pieceby rotating it in engagement with a grinding wheel transversely shapedin conformity with the desired spherical shape to be formed.

The foregoing and numerous other important objects,

advantages and inherent functions of the invention will be more fullyunderstood from the following description, which taken in connectionwith the accompanying drawings, discloses preferred embodiments of theinvention.

Referring to the drawings:

FIG. 1 is a side elevation view of a razor embodying the presentinvention;

FIG. 2 is a top view of the razor shown in FIG. 1;

FIG. 3 is a sectional view taken substantially along the line 33 in FIG.2;

FIG. 4 is an elevational view of apparatus for grinding a convexspherical surface on razor blade elements embodying the presentinvention and showing the blade element in transverse section; and

FIG. 5 is a view similar to FIG. 4 but showing grinding apparatuswherein the grinding wheel may be rotated about both axes while theblade remains stationary.

To illustrate the invention the drawing shows a razor 1] comprising athin, sheet metal blade 13 supported in a preferably molded handle 15 ofsuitable plastic or other readily moldable material. The blade elementis formed with one or more preferably circular holes, openings orperforations l7 therethrough, the margins of said openings beingsharpened to form peripheral, inwardly facing, fine cutting edges 19around the holes 17.

As shown more particularly in the drawing, the razor may comprise asingle, spherically curved plate or blade 13 formed with a plurality ofspaced holes 17 extending therethrough, said holes being preferablycircular and having a diameter of the order of four to five-tenths of aninch. Eminently satisfactory results are realized where the diameter ofthe openings is precisely 0.437 of an inch, although obviously theopenings need not be held precisely to the size mentioned. While theplate 13 may be formed with a single opening, if desired, it ispreferable to provide three or more equally spaced openings, preferablyarranged circularly about and equally spaced from a central point. Asshown, it is convenient to provide a spherically curved blade 13 havinga circular marginal edge and provided with four circular openings inequally spaced circular arrangement about the center of the plate.

In order to manufacture the razor blade, a thin disc of suitable razorblade material, such as carbon steel, tool steel, stainless steel andthe like, may first be blanked to size. It may then be pressed orotherwise shaped to the desired spherical configuration, the radius ofcurvature being preferably of the order of 2 inches. The convex side ofthe blank may then be ground precisely to form a surface 20 having thedesired radius of curvature. The holes 17 may be pierced, punched orotherwise formed in the disc, after which beveled surfaces 21 may bemachined at the edges of the openings 17, on the concave side 23 of theplate 13, and also at its peripheral edge. The blade may then betempered to obtain desired hardness.

Finally, the handle 15, which may be made of high-impact styrene, nylonor like material, may be applied to the peripheral edges of the blade13, as by injection molding, said handle, preferably comprising acylindrical portion 22, having a seat 24 securely receiving the beveledperipheral edge of the plate 13, at one end of said cylindrical portion.The handle also preferably has an outwardly extending flange 25 spacedaway from the seat 24. The periphery of the flange 25 may be roughenedby diamond knurling the same, as shown at 27, to provide firm fingergrippage for the manipulation of the razor.

It will be seen from the foregoing that the present invention pertainsto a new type of razor which may be used for shaving hair from thesurface S of any part of the body, and particularly to a novel method ofgrinding to form the cutting edges thereof. The razor of the presentinvention is of unique construction in that it does not require anyspecial type of holder or guard for the blade. The razor is unusual,also, in embodying a spherical blade element having one or more holesmarginally ground to a fine, sharp cutting edge is pressed upon andwiped across the surface to be shaved, the skin protrudes itselfslightly into the hole, thereby exposing the hairs of shaving. Byapplying a circular motion of the razor, a shearing action is producedupon the hairs, because of the mutually inwardly facing character of theshaving edge. Accordingly, a smooth, clean shave may be obtained with aminimum of shaving strokes.

By providing a plurality of relatively small razor edged holes, thepossibility of cutting the skin while shaving is minimized, and, indeed,substantially prohibited. The reason why inadvertent cutting of theskin, while shaving, is substantially inhibited, is, first, because thearea of skin exposed in the blade opening is relatively small, and,second, because there is no opening disposed centrally in the razor; butthe hole or holes are all offset radially from the center of the razor,the several shaving openings being all grouped circularly around thecenter of the razor. As a consequence, when the razor is held by the rim27, the cutting action is always of shearing character while the razorgyrates circularly across the surface of the skin being shaved. If acentered hole were to be provided in the razor, it would be possible torotate the razor about the center of the shaving opening, in which casethere would be a tendency to cut a circle of skin without cutting anyhair. It is therefore desirable that no shaving opening be centered inthe razor.

The number of shaving openings and their relative size may be varied, ofcourse; but it has been experimentally determined that four holes,having a diameter of the order of 4 to five-tenths of an inch, that isto say seven-sixteenthstone-sixteenth of an inch, at the honed cuttingedges thereof, and disposed about the center of the razor, in the mannershown in FIG. 2 of the drawings, appears to be a practical andsatisfactory, if not optimum, arrangement.

The unitary spherically curved blade of the razor shown in FIGS. 1-5 isunique in that the cutting edges of the blade are formed by theintersection of two spherical surfaces, so that a sharp cutting edge maybe easily ground and lapped or honed, since it is unnecessary tomaintain any close tolerance relationship between the outside radius ofthe blade, which is preferably of the order of 2 inches, and thespherical radium of the inner inclined sides 21 of the cutting edges, atthe several openings, which is of the order of one-half inch. Theseinner inclined sides of the cutting edges are preferably ground andlapped by a ball having a diameter of the order of 1 inch, as shown moreparticularly in my above referred to U.S. Pat. No. 3,522,678.

This form of blade has an inherent design limitation in that the angleof incidence of the cutting edges 19 upon the surface S being shaved,which cannot be varied, is determined by the curvature of the outerspherical surface of the blade element 13. [t has been determined that,under certain circumstances, it is desirable to have a somewhat steeperangle of incidence of the cutting edge with respect to the surface beingshave, that is to say, an angle that provides more scraping action.This, of course, could be accomplished by bulging the edges of each holeoutwardly, thereby making the grinding of the cutting edge extremelydifficult because of the necessity of working upon the outer surfaces ofconically bulged edge portions of the holes.

As shown more especially in H68. 4 and 5 of the drawing, the convexsurface of the blade 13, may be formed by grinding the same with agenerally concave spool-shaped wheel 31, preferably mounted for rotarygrinding movement about its axis 32. The side surfaces of the wheel aredressed to the sectional shape of the spherical curvature desired in theblade. The blade 13 to be lapped may be mounted on a support base 33having a spherical blade carrying portion 35, upon which the blade maybe secured in any preferred fashion, as by means of cement. The support33 has an axis 37 extending centrally of the spherical portion andthrough the center of curvature thereof, and the blade element to belapped is secured on the support with its center coincident with theaxis 37. The grinding wheel and support base with blade element securedthereon may then be brought into grinding relationship presenting theblade element against the shaped side of the wheel, with the axis 37 ofthe support extending normal to the axis 32 of the wheel and in themedial plane of its dressed surface, that is to say, its plane ofminimal diameter.

For optimum grinding performance, the wheel 31 and blade carryingsupport 33 should be relatively rotated about the axis 37. This may bedone by rotating the support and mounted blade about the axis 37 whilespinning the grinding wheel about its rotary axis 32. Alternately, thesupport 33 and mounted blade may remain stationary and the spinningwheel 31 may be mounted in a trunnion 38 for rotation about the axis 37while spinning about the axis 32. In either case the dressed wheel willgrind the desired spherical curvature into the convex surface of theblade mounted on the support 33.

It is thought that the invention and its numerous attendant advantageswill be fully understood from the foregoing description, and it isobvious that numerous changes may be made in the form, construction andarrangement of the several parts without departing from the spirit ofscope of the invention, or sacrificing any of its attendant advantages,the forms herein disclosed being preferred embodiments for the purposeof demonstrating the invention.

lclaim:

l. The method of grinding the convex outer surface of a thin razor bladehaving a spherically convex outer surface and a spherically concaveinner surface and having a plurality of edge sharpened openingstherethrough, which comprises mounting the blade on a support, placingin contact with the convex surface thereof a generally concavespool-shaped grinding wheel having a spinning axis and an arcuategrinding surface formed to the sectional shape of the sphericalcurvature of said convex surface, and simultaneously spinning thegrinding wheel about its spinning axis and relatively rotating thegrinding wheel and blade about an axis which is normal to said spinningaxis and which extends through the center of the blade, while in contactwith said convex surface of the blade.

2. The method of grinding defined in claim 1 wherein the step ofrelatively rotating the grinding wheel and blade is accomplished byrotating the grinding wheel and maintaining the blade stationary.

"M050 UNETED STATES PATENT @FMEE 5, 3 Dated January 4, 1972 Patent No.

Inventofls) Harold W. Scholin It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line 5, "may" should read my line 50, "element is" should readelement 13 is line +8, "thin, sheet" should read thin sheet Column 2line 26, "edge is" should read edge around the borders of the hole orholes. when the spherical blade line 28, "of" should read for Signed andsealed this 1 8th day of July I 972 (SEAL) EDWARD MOFLETCHER,JRQ ROBERTGOTTSGHALK Attesting Officer Commissioner of Patents

1. The method of grinding the convex outer surface of a thin razor bladehaving a spherically convex outer surface and a spherically concaveinner surface and having a plurality of edge sharpened openingstherethrough, which comprises mounting the blade on a support, placingin contact with the convex surface thereof a generally concavespool-shaped grinding wheel having a spinning axis and an arcuategrinding surface formed to the sectional shape of the sphericalcurvature of said convex surface, and simultaneously spinning thegrinding wheel about its spinning axis and relatively rotating thegrinding wheel and blade about an axis which is normal to said spinningaxis and which extends through the center of the blade, while in contactwith said convex surface of the blade.
 2. The method of grinding definedin claim 1 wherein the step of relatively rotating the grinding wheeland blade is accomplished by rotating the grinding wheel and maintainingthe blade stationary.